A true confession: this was originally intended to be a test image. I don't normally do landscape photography against a cloudless sky. But to my eye the "star" in this image is the cloudless azure-blue sky. I've rarely seen blue skies in a photographic image that are this deep and intense. Now this "test" image has become one of my favorite Gila mountain panoramas.

I suspect the intensity of this blue is a result of aiming the camera due north, which is almost perpendicular to the direction of the sunlight at the hour and time of year this image was captured. I believe that combination of angles created a polarizing effect.

Photographers use polarizing filters to reduce glare off of reflecting surfaces but also to make blue skies a deeper shade of blue. But no polarizer was used to create this image; the polarizing effect was already there.